Page 983 - Veterinary Immunology, 10th Edition

immunity. Thus they are the major source of the plasma cell
VetBooks.ir survival factor, APRIL (activation and proliferation-induced ligand)

(see Box 15.2). They are required for the homing of plasma cells to
the bone marrow and for their long-term survival. An absence of

eosinophils prevents efficient B cell class switching to IgA within
Peyer's patches. In effect, eosinophils generate and maintain
mucosal IgA plasma cells.
In conclusion, type I hypersensitivity reactions are mediated by

IgE and recruit three key cells: mast cells, eosinophils, and
basophils, to participate in the reaction. Their biological role is
likely to mediate antiparasite responses but, under modern
conditions, they also mediate allergic diseases.

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